By default, the boost test option is mandatory for build environment
detection. 
This patch suppress this dependency and allows the test part only if
build_test is enabled at the Buildroot level.

Signed-off-by: Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>
---
Index: gnuradio-3.7.5/volk/cmake/VolkBoost.cmake
===================================================================
--- gnuradio-3.7.5.orig/volk/cmake/VolkBoost.cmake
+++ gnuradio-3.7.5/volk/cmake/VolkBoost.cmake
@@ -29,7 +29,6 @@ set(__INCLUDED_VOLK_BOOST_CMAKE TRUE)
 set(BOOST_REQUIRED_COMPONENTS
     filesystem
     system
-    unit_test_framework
     program_options
 )
 
Index: gnuradio-3.7.5/volk/lib/CMakeLists.txt
===================================================================
--- gnuradio-3.7.5.orig/volk/lib/CMakeLists.txt
+++ gnuradio-3.7.5/volk/lib/CMakeLists.txt
@@ -540,8 +540,9 @@ endif(ENABLE_STATIC_LIBS)
 # Build the QA test application
 ########################################################################
 
+find_package(Boost "1.35" COMPONENTS "unit_test_framework")
 
-if(Boost_FOUND)
+if(Boost_FOUND AND BUILD_TEST)
 
     set_source_files_properties(
         ${CMAKE_CURRENT_SOURCE_DIR}/testqa.cc PROPERTIES
@@ -558,4 +559,4 @@ if(Boost_FOUND)
     target_link_libraries(test_all volk ${Boost_LIBRARIES})
     add_test(qa_volk_test_all test_all)
 
-endif(Boost_FOUND)
+endif(Boost_FOUND AND BUILD_TEST)
